500 Field Experiments on Root-Croj)s. 



the greater amount of constitutional disturbance wliicli marks 

 their progress. Once satisfied that the extent of the mischief is 

 such as to preclude all hope of remedy, the flockmaster must 

 have recourse to the butcher's knife as soon as possible, as the 

 whole system now rapidly becomes so thoroughly impregnated 

 with urine, that the meat is no longer wholesome as food. 



Such is the brief history of a disease which has of late years 

 prevailed very largely in this part of the country, and has there- 

 lore come frequently under my observation. 1 have taken con- 

 siderable interest in the subject, and given some attention to the 

 causes, nature, and treatment of the malady ; and these remarks are 

 simply the practical conclusions and deductions at which I have 

 arrived. It would have been easy for me to have extended and 

 amplified the views here expressed, but I have preferred to be as 

 concise and practical as possible, believing that I should thus 

 be better understood and appreciated by those who have the 

 deepest interest in this matter. Such is unquestionably the par- 

 ticular object of these papers, and I confess I am not without 

 hope, therefore, that the sheep-farmer may find something of 

 value and importance in what 1 have here written. 



Shrewsbm'y. 



XII. — Field Experiments on Root-Crops. By Dr. Augustus 



VOELCKEE. 



GeNEKAL ideas respecting the properties of manures, the chemical 

 and physical character of fertile and sterile soils, the require- 

 ments of plants, and the composition and uses of our crops, 

 no doubt are useful in awakening and sustaining a spirit of 

 inquiry amongst agriculturists. But, in addition to a sound 

 knowledge of the rudiments of chemistry and physiology, a man 

 must be acquainted with special facts before he can turn to 

 profitable account any chemical or physiological knowledge 

 which he may possess. 



It is no doubt useful to any person who is in the habit of 

 spending money in purchased manures, to know the composi- 

 tion of genuine and adulterated guano, or that of good and bad 

 superphosphates ; for such knowledge will guard him against 

 imposition, and enable him to buy the manures he requires of 

 the best quality, and at a reasonable price. It is not enough, 

 however, for him to be acquainted with the composition of the 

 various artificial manures now sold in the market, if he wishes to 

 apply his chemical knowledge to the best advantage. In order 

 that he may do this, he must likewise know how, when, and in 

 what quantities, guano, or superphosphate, or nitrate of soda, 



